The replacement of a diseased or damaged vertebral body located between adjoining healthy vertebral bodies has been disclosed in the prior art. One such method involved the placement of screws or metal rods driven into the inferior and superior vertebral bodies above and below the defective vetebral body. The screws or rods were then encased in acrylic cement which was cast in place. One problem which existed with this method is that the vertebral bodies above and below the defective vertebral body were too close together. To solve this problem, a force was used to distract the two vertebral bodies in order to restore the proper length of the spine and to correct angulation. In order to supply this force, a speading device must be placed between the two vertebral bodies and expanded. However, the cement cannot be poured and allowed to harden with the spreader in place, or the spreader will be incorporated in the hardened cement. If the spreader is removed prior to pouring, the adjoining vertebrae spring together and the desired length correction is lost. Cervical traction has been applied in a prior art method to establish the proper interspace of a removed vertebral body.
The use of an adjustable prosthesis between two adjoining vertebral bodies has also been disclosed in the prior art. In addition, the use of a posterior spinal plate to connect the spinous processes of the adjoining vertebral bodies in conjunction with the use of an expandable prosthetic vertebral body has also been disclosed.
Although a number of methods and devices have been disclosed in the prior art for replacing a diseased or damaged vertebral body, the maintaining of the proper spacing between adjoining vertebral bodies while a castable material was hardened in the cavity left by the removed vertebral body has not been possible.